An example of the above-mentioned motor driven shutter is disclosed, for example, in Japanese Published Unexamined Patent Application No. 3-89331. In this shutter, two sets of sectors are used to increase the shutter speed; that is, one set of sectors serves to open the shutter at a high speed, and the other set of sectors serves to set the aperture of the diaphragm and further to close the shutter. In other words, when not released, the first set of sectors are closed for light shading, and the second set of sectors are opened so as to provide a required exposure. When released, the first set of sectors are opened at high speed, and the exposure is attained through the second set of sectors. The exposure is completed when the second set of sectors are closed at a predetermined timing.
In the prior art motor driven shutter, however, since a second sector actuating electromagnet, a first sector actuating electromagnet, and an electromagnet controlling circuit for controlling these magnets are required as the control means, in addition to the stepping motor as the driving control means, the structure thereof is complicated; the structure is large and its cost is high and therefore the structure is subject to increased problems.